| /* |
| * Copyright (C) The Apache Software Foundation. All rights reserved. |
| * |
| * This software is published under the terms of the Apache Software |
| * License version 1.1, a copy of which has been included with this |
| * distribution in the LICENSE.txt file. */ |
| |
| package org.apache.log4j.helpers; |
| |
| import org.apache.log4j.spi.LoggingEvent; |
| import org.apache.log4j.spi.LocationInfo; |
| |
| /** |
| Utility class for transforming strings. |
| |
| @author Ceki Gülcü |
| @author Michael A. McAngus |
| */ |
| public class Transform { |
| |
| private static final String CDATA_START = "<![CDATA["; |
| private static final String CDATA_END = "]]>"; |
| private static final String CDATA_PSEUDO_END = "]]>"; |
| private static final String CDATA_EMBEDED_END = CDATA_END + CDATA_PSEUDO_END + CDATA_START; |
| private static final int CDATA_END_LEN = CDATA_END.length(); |
| |
| /** |
| * This method takes a string which may contain HTML tags (ie, |
| * <b>, <table>, etc) and replaces any '<' and '>' |
| * characters with respective predefined entity references. |
| * |
| * @param input The text to be converted. |
| * @return The input string with the characters '<' and '>' replaced with |
| * &lt; and &gt; respectively. |
| * */ |
| static public String escapeTags(String input) { |
| //Check if the string is null or zero length -- if so, return |
| //what was sent in. |
| |
| if( input == null || input.length() == 0 ) { |
| return input; |
| } |
| |
| //Use a StringBuffer in lieu of String concatenation -- it is |
| //much more efficient this way. |
| |
| StringBuffer buf = new StringBuffer(input.length() + 6); |
| char ch = ' '; |
| |
| int len = input.length(); |
| for(int i=0; i < len; i++) { |
| ch = input.charAt(i); |
| if(ch == '<') { |
| buf.append("<"); |
| } else if(ch == '>') { |
| buf.append(">"); |
| } else { |
| buf.append(ch); |
| } |
| } |
| return buf.toString(); |
| } |
| |
| /** |
| * Ensures that embeded CDEnd strings (]]>) are handled properly |
| * within message, NDC and throwable tag text. |
| * |
| * @param buf StringBuffer holding the XML data to this point. The |
| * initial CDStart (<![CDATA[) and final CDEnd (]]>) of the CDATA |
| * section are the responsibility of the calling method. |
| * @param str The String that is inserted into an existing CDATA Section within buf. |
| * */ |
| static public void appendEscapingCDATA(StringBuffer buf, String str) { |
| if(str == null) { |
| buf.append(""); |
| return; |
| } |
| |
| int end = str.indexOf(CDATA_END); |
| if (end < 0) { |
| buf.append(str); |
| return; |
| } |
| |
| int start = 0; |
| while (end > -1) { |
| buf.append(str.substring(start,end)); |
| buf.append(CDATA_EMBEDED_END); |
| start = end + CDATA_END_LEN; |
| if (start < str.length()) { |
| end = str.indexOf(CDATA_END, start); |
| } else { |
| return; |
| } |
| } |
| |
| buf.append(str.substring(start)); |
| } |
| } |